1. Field of the Invention
This invention relates generally to regenerators in gas turbine engines and, more particularly, to a seal assembly for the gaps between a regenerator matrix disc and adjoining portions of the gas turbine engine.
2. Description of the Prior Art
In typical gas turbine regenerator systems, a matrix disc is mounted on the engine for rotation about an axis perpendicular to nominally flat circular end surfaces of the disc. The disc rotates through streams of hot exhaust gas and relatively cold compressed air and thereby transfers heat from the hot stream to the cold stream. Because leakage from and/or between the streams must be minimized, leaf-type seal assemblies have been proposed in which a thin metal strip with an integral mounting flange along one edge is rigidly attached at the mounting flange to the engine while the other edge of the strip bears against a seal face of a flat platform disposed between the matrix disc and the metal strip. The platform functions to isolate the metal strip from rotation of the disc. Thermal gradient induced warpage or distortion of the matrix disc and platform during operation creates localized reductions in the gap between the platform and the adjoining portion of the engine. The local reductions in gap dimension tend to flex the metal strips relative to their initial configuration which flexure is resisted at the junction between the flange and the seal strip. Accordingly, it is characteristic of such seals that fatigue inducing stress concentrations develop at the junctions between the attaching flanges and the remainders of the strips. A seal assembly according to this invention seals the gap between the matrix disc and the engine with metal strips which are not rigidly clamped along either edge so that development of stress concentrations is avoided.